GitHub repo: https://github.com/ONLYOFFICE/sdkjs/blob/50708b3110a452ad79b8498a84bc8616069069b5/cell/apiBuilder.js#L2625
Function examples: https://helpcenter.onlyoffice.com/ONLYOFFICE-Editors/ONLYOFFICE-Spreadsheet-Editor/UsageInstructions/InsertFunction.aspx